Union forces under Major GeneralQuincy Gillmore attempted to retake the fort at the mouth of the harbor. Union gunners pummeled the fort from their batteries on Morris Island. After a severe bombing of the fort, Beauregard suspecting an attack replaced the artillerymen and all but one of the fort's guns with 320 infantrymen, who repulsed the naval landing party. Gillmore had reduced Fort Sumter to a pile of rubble, but the Confederate flag still waved over the ruins.